Added == and != comparisons to PoolAllocator required by GNU STL.
Added == and != comparisons to PoolAllocator required by GNU STL.

bitfusionio/Oclgrind,surround-io/oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind